Thread: Trisexual Reproduction Possible?

Today I was learning about sexual reproduction in science class, and I am wondering if it might be possible for 3 or more parents to produce offspring. I know there are no organisms that can do this, or atleast that i know of.

If it did work i think instead of having a pair of 2 chromosomes, the organism could have groups of 3 so if an organsim has a diploid number of 42 chromosomes it would get 14 chromosomes from each of the three parents instead of the normal 21 chromosomes from each of the 2 parents. instead of XX being female and XY being male, there would be XXX as female XYY as male and the third sex which could possibly look like something inbetween female and male would be XXY. there would still be an equall chance for an offspring to become either of the three sexes, and still no chance off an offspring ending up with YYY.

As far as mating goes the male would mate with the third sex. The sperm would go inside of the third sex some how, where a different kind of reproductive cell would fuse with them. Then the third sex would mate with the female and send the preveiously combined sex cells into the female were they would fuse with the egg to form a zygote made from 3 different sex cells, to eventually develope into a baby.

The problem with this could be that the animals might not know enough to mate in that order. however this might help cause less sameness in offspring which is the maine point of sexual reproduction.

does anyone else think this may be a practicle method of reproduction?

Originally Posted by Redeyedwolfking

does anyone else think this may be a practicle method of reproduction?
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Well, you've certainly found a practical way to scare the shit out of me. Seriously, I don't think this is very practical, as we'd have tons of hesheshe, and sheheshes, and most people (including me), would not appreciate that. I think we are perfectly fine with two genders, and while the idea of trisexual reproduction is interesting, I don't think it is a great idea.

Recommended reading: "The Gods Themselves" by Isaac Asimov.

Originally Posted by Moonbeam

Recommended reading: "The Gods Themselves" by Isaac Asimov.
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I love that book!

wich was your favourits: his robot stories, his foundation saga, or his black widowers?

back on topic ...

what would each partner be responsable for?

one for the egg, one for sperm ... and one as the "mom"?

Originally Posted by Keeper

I love that book!

wich was your favourits: his robot stories, his foundation saga, or his black widowers?

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Actually his fiction wasn't my favorite; there were a lot of SF writers I like better. What I really liked was his collected essays on scientific topics. Excellent writing and he made complicated things interesting. I still have a bunch of these really old paperbacks that cost like 25 cents new that I found in used book stores when I was a kid, I can't bear to get rid of them. Very educational and influential on my life.

I don't think it's practical as having 2 parents seems to work just fine and the organisms would instinctually know how to breed in the right order. For example, when the first male or however you classified it was fertilized, it could produce a pheremone or undergo a physical change (like hair loss or something) to indicate to the thrid partener that it's ready to breed.
Or this could give a whole new meaning to the term "threesome".
Also, there is also a greater chance for dysjunction to occur when the cells must undergo the entire process of meiosis twice, making this a less effective way of transfering genes IMO.
Cool though...
Makes me wonder, what conditions would cause a species to need to evolve into three different sexes?

Originally Posted by Moonbeam

Recommended reading: "The Gods Themselves" by Isaac Asimov.
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Sounds like a very good book. I didn't have the same idea on trisexual reproduction as this guy. but his seems like it would work.

Originally Posted by Moonbeam

Makes me wonder, what conditions would cause a species to need to evolve into three different sexes?
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I was thinking if a species needs to reproduce in small groups then it would cause more variation, but now that i think about this, i dont know if that would be true, because if you had 4 people left on earth then if there are 2 males and 2 females they would probably cause more variation with the normal method( 4 sets of parents), instead of there being 3 sexes and an extra of one sex. that would only make 2 different sets of parents. and they would have to hope that they had atleast 1 of each sex.

Originally Posted by Moonbeam

what would each partner be responsable for?


one for the egg, one for sperm ... and one as the "mom"?
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I was thinking the female would give both the egg and have the baby. But the other 2 could still help take care of the baby, maybe the third sex could provide milk. the third sex would not provide the sperm or the egg but it would have another sex cell that combines with the sperm.

would be a bit inificent, though, wouldn't it?

I actually thought about that too once... it seems pretty hard to pull off for nature, and it has no advantages compairing to disexual reproduction...

It is possible, but extremely unlikely.

Yeah, I read that book, Estwald was the super genius if I am remembering correctly.

Asimov was a science fiction writer, I am wondering what some of the more socially based science fiction writers could do with his characters. Someone line Ursula LeGuin, Vonda McIntyre, or Peirs Anthony.

Imaging the interpersonal relationship dynamics with three sexes.

I think requiring three genders to complete the reproduction process could very much be a disadvantage. It's a lot of work for not a lot of benefit, quite a sufficient amount of variation is achieved through male/female reproduction and evolution is about survival of genes, not variation. If you make the sexual process much more complicated than 'go hump any orifice', that's not good. Getting the right orifice is already something of a roulette game - the finer points of which still elude some of the human race - and having to get the right orifices in the right order sounds kind of complicated (even for me). It'd be a lot of luck to get evolution to hit upon the idea, being as a new gender and all the contemporary ways of having sex would have to be changed all at once to accommodate for this new gender. If you vary too much too quickly then there are going to be a lot more failures and a lot less possible partners as the genetic range gets wider. Bear in mind I don't know this, this is just what I'm thinking. I'm sure a much more qualified biologist could put my thoughts to shame with some pretty simple textbook knowledge.

I think it's complicated, the benefits are negligible and gee wouldn't that be weird. Not that say it isn't impossible. And it certainly would be interesting to see the dynamics (I can live without seeing the copulation part) in relationships. At least you could gang up on one person to take out the trash in the family house, or go out for a meal with one of your partners while the other babysits. Conveninent in the hectic modern world, although I can imagine scheduling being a nightmare.

But I'm missing the big point here. This entire three-gender plan really menaces the speed dating industry - you can't quickly switch tables unless you've got some complicated schematic for the table rotation. So, a lot of angry speed dating companies would put so much pressure on genetic engineers (or God/evolution depending on your club membership), so it won't happen. Can you imagine anyone being happy about their lucrative market being ruined by a piffling third gender? Can you imagine how much more space you'd need to have a third gender toliet?

What about the lavatory seat equilibrum? Men will put the seat up, women will put it down - a nice balance that causes no end of the old happy family argument. Then Mr. (Mrs?) Third-Gender over there decides he's going to just do something entirely different and tears the seat off its hinges. Now what are people going to argue about? Chaos. Chaos I say!